Mold for UV assisted nanoimprint lithography and methods for making such a mold

Abstract

A mold for nanoimprint lithography assisted by a determined wavelength is disclosed. According to some aspects, a layer made from a first material including, on a first face, a layer made from a second rigid material in which n structured zones with micrometric or nanometric patterns (n≧1) are made, and, on the face opposite said first face, a layer made from a third rigid material in which n recesses are formed, opposite the n structured zones. The n recesses are filled with a fourth material to form n portions. The transmittance at the determined wavelength of the layer of third material is lower than the transmittance of any one of the n portions; and the transmittance of the layers of first, second, and third materials at the determined wavelength λ det is such that the transmission of a light with determined wavelength λ det through said layers is lower than the transmission of the light through any one of the n portions and the layers of first and second materials. According to some aspects, methods for making such a mold are disclosed.

What is claimed is: 
     
       1. A mold for nanoimprint lithography assisted by a determined wavelength λ det , comprising an intermediate layer made from a first material and having two opposite faces, a lower layer, provided on a surface of one of the opposite faces of the intermediate layer, made from a second material, the second material formed as a rigid material, and in which n structured zones with micrometric or nanometric patterns are made, n being an integer greater than or equal to 1, and, an upper layer, provided on a surface of the other one of the opposite faces of the intermediate layer, made from a third material, the third material formed as a rigid material, in which n recesses are formed opposite the n structured zones of the lower layer, the n recesses being filled with a fourth material to form n portions;
 wherein the upper layer has a thickness and a composition such that its transmittance to light for a determined wavelength λ det  is lower than the transmittance to light for the determined wavelength λ det  of any one of the n portions, and 
 wherein the transmittances of the upper, intermediate, and lower layers at the determined wavelength λ det  are such that the transmission of a light for the determined wavelength λ det  through the upper, intermediate, and lower layers is less than the transmission of the light for the determined wavelength λ det  through any one of the n portions and the intermediate and lower layers. 
 
     
     
       2. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the transmittance of the upper layer has a value less than or equal to ⅔ of the value of the transmittance of the fourth material of the n portions. 
     
     
       3. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the transmission of the light for the determined wavelength λ det  through the intermediate, lower, and upper layers less than or equal to about 20%, and the transmission of the light for the determined wavelength λ det  through any one of the n portions and the intermediate and lower layers is greater than or equal to about 65%. 
     
     
       4. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the n recesses have a depth equal to the thickness of the upper layer. 
     
     
       5. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the n structured zones are formed in the entire thickness of the lower layer. 
     
     
       6. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the first material is a flexible material, and wherein the lower layer has a non-zero thickness outside the n structured zones. 
     
     
       7. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the fourth material is a flexible material. 
     
     
       8. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the determined wavelength λ det  is situated in the UV wavelength range. 
     
     
       9. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the first material is silica or silicon nitride, the second material is silica or silicon nitride, the third material is silicon and the fourth material is polydimethylsiloxane (PDMS). 
     
     
       10. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the transmittance of the upper layer is less than or equal to about 0.2, and the transmittance of each of the n portions is greater than or equal to about 0.65. 
     
     
       11. The mold for assisted nanoimprint lithography according to  claim 10 , wherein the transmittance of the upper layer is less than about 0.1 and the transmittance of each of the n portions is greater than about 0.85. 
     
     
       12. The mold for assisted nanoimprint lithography according to  claim 1 , wherein the first material is a rigid material and wherein the lower layer is present only at the n structured zones. 
     
     
       13. The mold for assisted nanoimprint lithography according to  claim 12 , wherein any two or more of the first material, the second material, and the third material are identical.